System to monitor the ingestion of medicines

ABSTRACT

A system for monitoring ingestion of medicine ( 21 ) comprises forming a digestible radio frequency identification (RFID) tag ( 10 ). The RFID tag is attached to the medicine. The RFID tag and medicine are ingested. A signal from the RFID tag is monitored.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 11/156,959 filed Jun. 20, 2005 and entitled SYSTEM TO MONITORTHE INGESTION OF MEDICINES, which is incorporated by reference herein inits entirety.

FIELD OF THE INVENTION

The present intervention relates in general to tracking ingestion ofmedication, and in particular to detecting proper use of medicationusing fragile radio frequency identification (RFID) tags.

BACKGROUND OF THE INVENTION

It is desirable to monitor internal bodily events, sometimes over aperiod of time, without immediate access to medical facilities. Forexample, the ability to track medicine ingestion and absorption into thebody is useful for verifying proper usage, monitoring drug interactions,controlling dosage and maintaining inventory control.

Traditional methods of obtaining internal physiological informationinclude: physically probing the body via an orifice or incision withtools such as endoscopes or laparoscopes; imaging the body withmodalities such as x-ray, computed tomography or magnetic resonanceimaging; or collecting biological samples such as blood, saliva, bodilysecretions, or biopsy tissue. It would be appealing to probe the livingbody without the effort, expense, inconvenience and risk of injury orinfection involved with the above methods.

An improvement on these traditional means is the use of ingestiblecameras, such as the Pillcam™ produced by Given Imaging (seewww.pillcam.com). These swallowable cameras in pill format collectimages and basic physical measurements such as pH and temperature asthey travel through the digestive tract. Pillcam's™ main use is tocollect internal images to help with diagnosis of conditions inside thedigestive tract. These devices have been proven to provide usefulinformation about the state of a subject without additional invasivemedical procedures. However, such cameras are relatively complex,expensive, unpleasant to swallow, and are limited in their ability tocollect physiological information.

Radio frequency identification (RFID) tags are a class of device thatcan also be applied to the problem of tracking internal physiologicalactivities. An RFID tag includes an antenna made of a material that canbe caused to sympathetically resonate by a field attuned to a particularfrequency (typically in the radio range). The resonance of the antennain the field in turn becomes a source of information by broadcasting atthe resonant frequency. These devices are more flexible in their rangeof applications, less expensive, simpler and therefore more robust thanthe solutions discussed above. As shown in FIG. 1, the standardcomponents of an RFID tag 10 include a circuit 12, a resonant cavity 14,and an antenna 16 assembled on a substrate 18 or other means ofproviding support to the components just stated. Current RFID technologyoffers many solutions that take advantage of a remote queryingcapability combined with decreasing cost.

RFID tags have a long history. During World War II the British used RFIDtags to remotely distinguish between friendly and hostile approachingaircraft. The World War II VT Fuze manufactured by the Eastman KodakCompany and others emitted a radio signal that responded to theproximity of a metal target by becoming increasingly in phase until thecombined strength of the emitted and reflected signals was sufficient toactivate the fuze.

Further evolution of the RFID tag occurred when. Thermin pioneered theuse of passive RF to spy upon the American Embassy in Moscow. Theprecursor to modern passive RFID tags, an external radio transmissionprovided power to a resonant circuit at certain frequencies. Certainconditions, such as people speaking in a room, would modify themodulation of the resonance, which would then be received anddemodulated, creating an extremely simple and robust wireless means forlistening to remote conversations.

More recently, RFID technology has been applied to the medical field ininventions such as affixing RFID tags 10, to containers for medicine 20,shown in FIG. 1, patients, and medicine dispensers, such as IV bottles.These RFID tags can be remotely queried in order to track the medicineusage. (See U.S. Patent Application Publication Nos. 2005/0088306 A1(Andreasson et al.) and 2004/0008123 A1 (Carrender et al.). One majorshortcoming of this approach is that the RFID tag is on the containerand not in the medicine that is ingested. Although usage can be tracked,a method that verifies ingestion and digestion of medicine by a specificperson cannot be implemented.

Although potentially useful, another approach is to provide RFID tagsthat can be implanted in a living body without fear of breakdown orinteraction. U.S. Patent Application Publication No. 2003/0058110 A1(Rich) refers to an RFID system that can be embedded under the patient'sskin. However, RFID tags that require implantation in the human body formonitoring biological activity and medicine delivery will also requireremoval when no longer needed, a near certainty for most conditionsneeding medicinal treatment. Permanently implanted devices and tagsrequire engineering and construction to attempt to preclude damage andfailure as is taught in U.S. Pat. Nos. 6,083,523, 5,874,099 (both toDionne et al.), and others by Dionne et al. and may be cost prohibitivefor the majority of the patient population. Simple systems of permanentRFID tags embedded under the skin have been developed for tracking andidentifying pets such as disclosed in U.S. Pat. No. 5,850,196 (Mowers)

Finally, in cases where the RFID tag is meant to pass through the body,as the Pillcam™ does, engineering is required to ensure that the RFIDtag circuit is not damaged in the process of ingestion and elimination,again potentially increasing the cost and size of the device.

Therefore a need exists for a system to accurately monitor a patient'singestion and digestion of medicine, without the use of permanentlyembedded equipment or cost prohibitive RFID solutions.

SUMMARY OF THE INVENTION

The need is met in the present invention by the incorporation of fragileRFID tags into medicine. Briefly, according to one aspect of the presentinvention a system for monitoring ingestion of medicine comprisesforming a fragile (which means destroyed by interactions within and withthe body and therefore not requiring removal because it has beendigested or otherwise assimilated) radio frequency identification (RFID)tag. The fragile RFID tag is introduced into the body by being attachedto the ingested medicine or by being otherwise embedded in the body.Once inside the body, the fragile RFID tag's signal is monitored.

Although radio frequency is the most often referred to wavelength inteaching this invention, this invention teaches embodiments that useother wavelengths and fields for remotely communicating with the fragiletag.

A fragile RFID tag contains an antenna made of a material that can becaused to sympathetically resonate by a field attuned to a particularfrequency (typically in the radio range). In this respect, the fragileRFID tag is similar and well understood to all previous art on creatingtags that can be remotely queried such as U.S. Pat. No. 5,682,143 (Bradyet al.) and U.S. Pat. No. 6,894,614 (Eckstein et al.). The resonance ofthe antenna in the field in turn becomes a source of information bybroadcasting at the resonant frequency. Normally such antennae arecreated of metals or biologically inactive metals such as gold in smallamounts such as in the form of a thin foil. When a pill is ingested, theantenna structure is destroyed over a period of time by the body. Otherforms of edible and conductive materials such as encapsulated metallicliquids, clays (such as Silly Putty) or even liquids or gases can alsobe used to create a suitably fragile antenna that would be destroyed inthe process of consumption without harming the consumer. Thesematerials, having been previously passed over for use precisely becauseof the their fragility and lack of robustness, are ingestible because ofthe small amounts that would actually be consumed since such ingestibleconductive materials need not comprise the whole of the device, but needonly be used in sufficient quantities and areas so that the function ofthe tag is comprised upon consumption. The need for RFID tags that canbe deactivated is touched on by U.S. Pat. No. 6,025,780 (Bowers et al.)when they teach a means of disabling a RFID tag, but they do not seek todesign a tag that is engineered to self-disable.

A home environment or a medical kiosk would have at least one constantRF source (such as those in use to detect RFID payment information ingas stations) that would recognize existence or nonexistence of anantenna. By having a plurality of RF sources, the 3D location of eachantenna can be determined. With a system to monitor the kind, existenceand location of each medicine the following devices and services becomepossible:

-   -   The lockable drug dispenser (who is attempting to take medicine;        what they took; preventing overdosing or reminding the patient        to take medicine)    -   A kiosk/bathroom attachment that insures the medicine is taken        on the spot (keeps the door locked until the medicine is taken)    -   A means of determining if the medicine was taken or dropped down        a toilet or sink    -   A means of reminding the patient which medicine to take by        tracking the medicine taking history    -   A means of sharing the medicine taking history with medical        staff    -   A means of guarding against medical interactions with food,        vitamins, and other medicines by using a medical tracking        history

This invention is a system that uses intentionally fragile tags toprovide useful information by identifying when such tags are destroyedor rendered inoperative. The system then responds to this basic changeof state by providing a useful service. Such intentionally fragile tagscan be composed of materials that not only can be ingested but alsodigested with the understanding that break down is a desirable qualityand one that enables the tag materials to be eliminated in the standardmanner. Such a fragile tag that is also digestible lends itself toapplications such as being included in objects meant to be ingested,such as pills, lozenges, and glycol strips.

Applications favored by such a system include tracking medicine, not bycontainer but the medicine itself; and tracking the medicine to itsdestruction by the body. Such a capability in turn enables systems thatautomatically dispense drugs with the ability to insure that the drug istaken on the premises otherwise exiting the premises can be curtailed.When combined with a means of uniquely identifying the medicine taker,the systems can track the frequency and dosage of the medicines takenand can be enabled to automatically limit or increase the dosages on thebasis of direct observation or to call for assistance on the basis ofmedicine taking behavior.

An additional application is where the fragile tag is engineered tobreakdown only in the presence of certain compounds, such as, but notlimited to, those found in the stomach. Such a system allows convenientand simple to administer drug testing. Such a system also allowsconvenient sample testing, for example, a urinalysis where the fragiletag is thrown into a toilet and the results are immediately remotelygathered and stored, thus eliminating the need for carrying around asample.

In another application, the fragile tag is engineered to breakdown undermechanical stresses rather than by chemical reaction. Such a tag may beaffixed to an artificial, or natural body part. It is then implanted andcan be remotely queried. When wear on the body part, for example, anartificial hip, has proceeded to a predetermined level, the tag isrendered useless thus alerting the remote query that the body part hasachieved an unsatisfactory level of wear.

Although the preferred embodiment describes a system utilizing radiofrequency identification tags, it should be noted that the simplicity ofthe system allows for the use of acoustical frequency identificationtags, as well as tags that reflect or resonate in other frequencies.Because existence or non-existence provides sufficient information toenable operation of the system, applications can be imagined where thecircuitry required in typical RFID tag systems is not required.

The preferred embodiment uses passive tags, but active tags can be ofequal or greater use in some instances. The preferred embodiment refersto a single tag but the invention encompasses the use of multiple tagsthat react in parallel. Multiple tags may be packaged so they areexposed to conditions in a serial manner, over time. Another embodimentuses multiple tags whose packaging yields useful information from somecombination of the tags being destroyed or surviving conditions, such aswhen compounds in the stomach destroy some tags but leave others.

The invention encompasses the extraction of data when conditionspartially destroy or otherwise modify a tag. The tag may additionally becomposed of compounds such as quantum dots, providing the addedfunctionality that when the tag is ingested, it breaks down intocomponents that can still be tracked by other means.

The invention includes the potential of being externally powered, forexample, an RF circuit and the device uses this power to activate orotherwise alter either a circuit that will release or restrict therelease of medicine in the body or that will alter the medicine itselfto render it active or inactive.

The invention and its objects and advantages will become more apparentin the detailed description of the preferred embodiment presented below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing showing a tagged medicine container and aradio frequency identification (RFID) tag.

FIG. 2 shows components of system for monitoring the ingestion of afragile RFID tagged medicine.

FIG. 3 is an illustration showing variations of monitor placement forthe system.

FIG. 4 is an illustration of a kiosk version of the system.

FIG. 5 is an illustration of a home version of the system.

FIG. 6 is a schematic drawing showing the flowchart for a sequence ofevents according to the present invention.

FIG. 7 is a flowchart of the system of the present invention processinginformation utilizing negative feedback.

FIG. 8 is a flowchart of the system of the present invention processinginformation utilizing positive feedback.

FIG. 9 is an illustration if a fragile RFID tag being destroyed in themouth.

FIG. 10 is an illustration of a fragile RFID tag suspended in a capsule.

FIG. 11 is an illustration of a compound fragile RFID tag.

FIG. 12 a is an illustration of a fragile RFID tag that is fragilebecause it is embedded to show mechanical wear at a joint.

FIG. 12 b shows an additional form of fragile RFID tag where multiplelayers of RF blocking material are used.

FIG. 13 is an illustration of an active fragile tag.

FIG. 14 is an illustration of a fragile RFID tag whose resonancecharacteristic change due to breakdown in a circuit designed to befragile.

FIG. 15 is an illustration of a fragile identification tag usingacoustical properties.

FIGS. 16A and 16B show an illustration of a fragile retro-reflectiveidentification tag.

FIG. 17 is an illustration showing the combination of a fragileidentification tag and non-fragile components such as quantum dots.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be directed in particular to elements formingpart of, or in cooperation more directly with the apparatus inaccordance with the present invention. It is to be understood thatelements not specifically shown or described may take various forms wellknown to those skilled in the art.

Referring now to FIG. 2, a system for monitoring ingestion of taggedmedicine 22 is shown. A digestible radio frequency identification (RFID)10 tag is carried by (that is, affixed to or embedded in) medicine 21 toform tagged medicine 22. When ingested, tagged medicine 22 is detectedby a monitoring device 30.

Monitoring device 30 is comprised of a storage device 32, an emitter 34,and a transceiver 36. These components are attached to a support 38which may be worn as a belt or otherwise affixed to a person's body.

Information from the monitoring device 30 may be transmitted to atransceiver 36 a, which is connected to a computer 42. Informationreceived from the monitoring device 30 is viewed on monitor 44.

Referring to FIG. 3, monitoring device 30 may be incorporated indifferent articles to be worn on the body. Some examples include collar52, lanyard 53, and belt 54. Monitoring device 30 may also be located inclose proximity to the mouth, for example on an earpiece and boom 25.Monitoring device 30 may also be incorporated in handheld devices 56,medicine dispensers 57, overhead apparatus 58, or wall mounted apparatus59.

In all cases, the monitoring device would function similarly. Whentagged medicine is ingested, an external RF emitter sends a signal thattravels through the body and causes a resonance in the RFID tag asdiscussed above. Thus, the travel of the medicine through the body canbe tracked at any point desired. For example, if the collar 52 is worn,the medicine can be detected as it is swallowed. If the belt 54 is worn,the medicine can be detected as it enters the stomach. And both of theseexamples, the monitoring device can also detect when the tagged medicinehas passed these points, as well as detecting when the medicine hasentered these points.

The concept can also be applied to environments other than that of astand-alone system. FIG. 4 shows how this can be applied at a medicalkiosk. A medical kiosk is a device that performs tests and checks on aperson, for example, blood pressure, weight, blood oxygen levels, streptests and others. The kiosk can have personal assistance, be unassistedor have a remote video links for assistance. With a fragile RFID tagthat can detect specific drugs or controlled substances, a kiosk can beutilized to test prescription or illegal drugs in person's bloodstream.In this case, the tag will activate when in contact with the specificdrug or substance of interest.

A subject 4 walks up to a medical kiosk 5. A fragile RFID 22 isdispensed and ingested. Ingestion can occur by the medicine andsubstance or drug-specific RFID tag being incorporated into a skin patchapplied by the subject. Upon contact with the substance of interest, asignal 3 is sent from the tag and is picked up by a monitoring device 30within the medical kiosk 5. A proximity detector 17 is utilized toensure that the subject 4 is within proper distance for the signal 3 tobe detected by the monitoring device 30 in the medical kiosk 5. Theinformation (ingestion, detection, or both) is recorded by the kioskcomputer 15, stored, printed, and or transmitted to a location ofinterest (doctor, supervisor, caregiver or the like).

Potential applications for this include illegal drug testing ingovernment and certain sporting situations (some observation would berequired to make certain the tag is applied or ingested and by theproper test subject). It could also be used in a elder care facility todetermine the level of prescription drugs that a subject was expected tobe ingesting and to monitor the actual ingestion of prescription drugsto get to the proper levels. Other application areas are those where thesubjects may be difficult to deal with in the taking of medications orother ingested materials (perhaps even a location sensor to positivelyidentify who and where a person is). Examples are school children,military personnel, prisoners and even pets.

FIG. 5 shows an implementation of the fragile RFID using a home system.Examples of application areas here include homebound individuals where adoctor or nurse needs to be informed of the proper ingestion ofmedications and the dosages that are being taken. Cardiac care patients,the elderly, those who must take many medications, people with memoryproblems or those in remote locations are examples of subjects. In thisembodiment, a device is attached to a typical home computer 19.Monitoring device 30 is a combination sensor and proximity detector thatconnects through one of the standard communication interfaces on thehome computer 19. This interface can be a USB, RS-232, or wirelessconnection and software that can determine if the subject 4 is withinthe proper distance for the sensor to be able to detect the signal fromthe RFID tag 22 as well as the detection itself. When the tag isingested, the signal 3 (either that the ingestion has occurred or itcontact with a substance of interest has been detected) is sent out andpicked up by the monitor 30. The signal (or lack of such) is thenrecorded, using the aforementioned software and stored on the homecomputer 19 or transmitted to another location, such as a doctor'soffice, a nursing station, caregiver, or other persons of interest.

Another embodiment that applies to FIG. 5 is that of a computer onwheels (COW) that are often found in hospitals. The same monitoringdevice 30 can be added here and a similar scenario will follow as for ahome PC. In addition, portable computers, laptops, tablet PCs, PocketPCs and even personal digital assistants (PDAs) can be utilized as longas a monitoring device can be utilized. Since most of these devices havewireless capability, this poses little problem.

A medicine dispenser 57 can also be part of this system and used to keeptrack of the medicines as they are dispensed. This information can becompared with the ingestion of the medicines to determine if they havebeen ingested as intended. The detail is explained later in FIG. 8.

FIG. 6 shows a sequence of events appropriate to the present invention.The patient's monitor is initially in an “off” state 40 since it isassumed that there is little benefit to having the monitor continuouslyon (although there may be case exceptions where there is a need to doso). Taking the medicine will involve opening or otherwise manipulatinga medicine dispenser 45 which will then send a signal that activates thepatient's monitor 50. The process then goes into a loop 47 waiting forthe detector's state to change 55 because it has detected the existenceof the tagged medicine. It is reasonable to assume that if no medicineis detected or if the tagged medicine is not destroyed within somepredetermined time limit, that the system will cease waiting andtime-out 60 resulting in exiting the loop by turning off the monitor 65and signal an appropriate (no tagged medicine or no tagged medicinedestroyed) incomplete end-data 70. For example, when a person opens (orotherwise activates) the medicine dispenser 45 but does not take themedicine, the time of the false event and the medicine involved shouldbe recorded and sent to a caregiver or other involved in monitoring thepatient's well being as related to medicine use. It should be noted thatthe patient and the caregiver may be one and the same person.

FIG. 6 further diagrams how after the tagged medicine has been sensed 75by the monitor, the data such as the identification and dosage of themedicine is read from the tag and combined 80 with other data such astime of day by the system of this invention. The data then can be stored85, transmitted 90, or be additionally processed 95 as desired by theusers of the system. For example, a caregiver may wish to be immediatelynotified of the act of the patient taking a particular medicine so thesystem is enabled to send a transmission 100 which may be the only stepso that the system function is done 105 and since the monitor “off”check is failed since finds the monitor “on” 110, the results aredisplayed 115 for the caregiver. The caregiver may also wish to have arecord of the medicine taken for later comparison against other vitalsigns and aspects of change in the patient's health so storage 120 wouldthen also be enabled. Finally, the caregiver may wish to compare thetime, dosage and identification of the medicine against rules for takingthe medicine so additional processing 125 of the data would also bedone. It is likely that all three steps would be done since the resultof processing 125 the data would likely lead to the need to transmit 100an alarm (a form of display in the understanding of this patent) ifcertain rules were violated and for the actions to be stored 120 forlater reference.

Upon completion of the desired steps related to verifying taking themedicine, that is when all the initial tasks required of the system aredone 105, the system confirms that the medicine is in fact taken bycontinuing to loop 47 through the process until the time-out limit isexceeded 60 or until the tagged medicine is destroyed causing a changeof state 55 which in turns fails the tag existence check 75 whichresults in the monitor being turned off 65 and the which causes theprocess to signal an end-data 70 which is followed by the stepsmentioned of checking whether transmission 100, storage 120 oradditional processing 125 is enabled for the time out or tagged medicinedestruction step. This final pass through the system encounters themonitor “off” check 110, and upon passing goes to the end state 130. Itshould be noted that inventions such as U.S. Pat. No. 5,963,136(O'Brien), and recently U.S. Pat. No. 6,851,615 (ones) and othersanticipate the need and appropriateness of using RFID tags for managingmedicine and medicine dispensers, but such inventions do not use aprocess that seeks and is able to validate that the proper dosage hasbeen take.

A special case exists when the fragile tag is designed to exist for alonger duration, such as when there is a need to indicate somethingother than immediate ingestion and consumption of a medicine. An exampleof such a need is wear of an internal structure such as bone at a jointor an implanted device such as a pacemaker, artificial joint, or similardevice. Unlike the process in FIG. 6, the process begins when a fragiletag attached to a device or the fragile tag itself is surgicallyotherwise embedded in the body. Therefore the step of the taggedmedicine being dispensed 45 is eliminated and the process begins withthe monitor being turned “on” through some other process, manual or someother automated trigger (presenting a unique identifier such as a cardwith data encrypted upon the card in some media, biometric data such asfacial recognition, or some additional form of tagging foridentification purposes) rather than a step of automatically turning themonitor “on” 50 as described in FIG. 6. At subsequent times, themonitoring process keeps looping 47 (albeit in loops of longerchronological duration then those waiting for the fragile taggedmedicine to be destroyed) and checking continues until the fragile tagis destroyed 55. The monitoring process can be manual using a handheldscanner, automatic wherein the patients present themselves to a scanningdevice built into a kiosk or semiautomatic where human observation iscombined with a mass screening system. When the tag ceases to exist themonitor sends the end data 70 described in FIG. 6 to the system and theappropriate actions are taken.

FIG. 7 provides a flowchart of representative processing steps for amore complex set of responses to the negative feedback loop of the sortdescribed in FIG. 6 as a general timing out loop 47 in the sequence ofevents comprising the invention and which is not meant to beall-inclusive. Unlike FIG. 6, FIG. 7 clarifies a case where the systemis constantly monitoring for the intake and/or destruction of thefragile tagged medicine. The loop 47 may respond with an additional loopbased on negative feedback information (such as “no fragile taggedmedicine has been detected”) by constantly looping where each loopresults in checking for a change of state 55. When there is no change,each loop additionally checks the time 135. The current time whenchecked 135 may then be compared to the patient history 140 to establisha relative time to some prior event (such as the taking of some othermedicine, time prior to sleep or time since having dinner) as opposed toa simple absolute passage of time as previously referred to in FIG. 6 instep 60 as checking for a time out. A comparison of relative time can beused to decide on whether it is the correct time to take medication 145such data can be compared to a database containing other timeinformation such as an absolute time for a particular medication to betaken as referred to in FIG. 6. This also provides a means to check onthe longitudinal consistency of proper and timely ingestion. Uponcomparison and determination if the medicine should be taken 145 thesystem can (if it is time to take the medicine) proceeds to a looking upa preferred action 150 and then executing the action 155; as opposed toFIG. 6 where the only action referred to was turning off the monitor 65and signaling end of data 70. A preferred action in this case may be aresponse such as turning on an audiovisual alarm that medicine needs tobe taken. Prompts other than time are also readily considered andfamiliar to those versed in the art of monitoring the state of apatient's condition relative to the need of the patient to takemedicine.

FIG. 8 continues the flowchart begun in FIGS. 6 and 7 representing amore complex loop 47 sequence of events. FIG. 8 represents a positivefeedback component to the loop 47 where information, specifically, thetest “has there been a change of state” 55 is passed and triggers apositive loop. Under conditions where the fragile tagged medicine hasbeen detected as being taken and/or destroyed and information has beenreceived from the fragile tag, and read 80, the step of reading andadding data 80 is followed by additional specific steps such as theidentification and thus, knowledge of location of a particular sensor160 and/or group of sensors and this information combined by the systemwith environmental information 165 such as (but not limited to) time.Other potential forms of environmental and personal data that might beof use are temperature, light levels, position or posture of thepatient, temperature of the patient, pallor, chemical balance of theblood, heart rate, oxygen levels and all other forms of patientinformation known to practitioners of the medical arts. By comparingsuch data to the larger patient history 170 useful conclusions about theimpact of taking the medicine can be drawn. As an example, acomputerized system can compare the medication and dosage prescribed tothe medication and dosage being taken and identify an error in dosage175 and issue an alarm if such is the preferred action 155, if there isan error. Similarly, the system can be programmed to recognizeappropriate aspects of the environment 180 such as the patientattempting to take a “photodynamic” drug such as sulfonamides,tetracyclines, sulfonylureas, thiazide diuretics, or nalidixic acid,where under sunlit conditions, such a drug would react adversely tosunlight. Another condition is based on the comparison to absolute andrelative times 185 for the medicine to be taken, particularly inconjunction with the proper circumstances and environment 180. Forexample, the patient should be not be taking the medicine too soon aftereating. Routinely, it is important to be aware of what medicine wastaken when in order to avoid taking an improper combination of medicines190 being taken. The system can in each case lookup 150 a preferredaction and, if so enabled, execute 155 the preferred action as a morecomplex variation on the option listed in FIG. 6 of simply displayingthe data.

It should be noted that the following illustrations are not meant to anddo not provide accurate scales and sizes, and are instead meant toillustrate the basic functional relationship of the components.

FIG. 9 schematically suggests that a fragile RFID tag 22 can be usefuleven if it does nothing more than cease to respond when chewed. In thisexample, the RFID tag antenna 16 is assumed to be made of a consumablematerial that also acts as a good antenna, such as copper. Silver, gold,or conductive polymers such as such as those taught in U.S. Pat. No.6,899,829 (Shelnut et al.) and many others going back to U.S. Pat. No.3,958,066 (Imamura et al.) and earlier are also suitable, includingthose noted by Shelnut's teaching being such colloidal compositions ashave a selectivity for non-conductive surfaces. It should be noted thatRFID antennas can be made of very thin films, in fact printed tags formail use are in the range of net tag thickness of 0.0008 inches astaught by U.S. Pat. No. 6,820,314 (Ferguson et al.), and still functionallowing for some latitude in the choice of materials for the antenna.In this example, the medicine is assumed to be in the form of chewablelozenge or a glycol strip such as those manufactured under the Listerinebrand and other mouth antiseptic products such as Listerine Pocketpaks™as found at www.oral-care.com. Designing for fragility requires that theductility of metal (if metal is used), or pliability of the conductivepolymer, tolerates handling but is not so great that the antenna or thepackaging interferes with its destruction when taken. As stated in thedescription for FIG. 3, a monitor mounted on a boom 25 or otherstructure or otherwise affixed to the skin inside or outside the mouthor embedded in a tooth then responds to presence and then the absence ofthe functioning fragile RFID tag as previously discussed in FIG. 6.

FIG. 10 illustrates a fragile RFID tagged capsule 200 with the antennaformed in a helical shape (or other appropriate three dimensionalfigure) as is well known in the art and as typically taught in U.S. Pat.No. 4,309,707 (James et al.), specifically that the antenna is not in aflattened form factor but the antenna is in a three-dimensional coil210, allowing compact encapsulation. The fragile RFID tag is thenencapsulated in a manner familiar to those versed in the art ofmanufacturing capsules of medicine. The gelatin coating typical of suchcapsules (or degradable polymer as taught by U.S. Pat. No. 5,914,381(Terado et al.) or other suitable coating) would dissolve in thestandard manner in the mouth or stomach allowing the fragile antenna tobe destroyed in accordance with the process outline in FIG. 6.

FIG. 11 illustrates a compound capsule 220 where more than one fragileRFID tag is encapsulated. Each fragile tag is encapsulated in adifferent substance, or in the same substance but where the substancehas been treated to react differently to its environment. So, capsule220 is constructed in different ways to resist dissolution to a varyingdegree. The same substance is varied in thickness or textured as isevident to the least gifted in the art of packaging medicine. Whenbiodegradable time-release medicaments as specified in U.S. Pat. No.4,093,709 (Choi et al.) are used, the same micro-spheres can be packedaround the different fragile RFID tags. The use of more than one capsule220 for encapsulating more than one tag and having such additionalcapsules linked in a single dose permits testing for compounds as wellas identifying rates of absorption. Multiple tags can interfere witheach other when responding to an RF source, so that the destruction ofone or more tags would reveal its identity by process of eliminationsince the remaining fragile tag could then be clearly identifiedproviding potentially useful information. Alternatively, the fragileRFID tag may be surrounded by micro-spheres of medicine that interferewith the RF signal much like a Faraday cage, in which case the fragileRFID tag would be detected by the monitor for a limited time between thedissolution of the surrounding materials and the dissolution of thefragile RFID tag. Additionally, subcarriers may be used as taught byU.S. Pat. No. 6,765,476 (Steele et al.) as well as other schemes thatallows the use of multiple RFID tags antenna in close proximity toanother by adjusting the use of monitors and antennas.

Compounds typical of those used to coat ingested capsules with differenttypes of reactivity to the environment found within the body are listedin patents found by searching time and release and medicine such as U.S.Pat. No. 4,707,362 (Nuwayser).

FIG. 12 a illustrates the use of a fragile RFID tag whose value isderived from mechanical wear of the tag 230. This example of use refersback to the special case mentioned at the end of the description of FIG.6 where the fragile tag is embedded in the body rather than ingested. Aclearly appropriate application for such an embedded fragile tag is aspart of a protective layer on top of bone 240 or other surface or bodypart that experiences wear. In the case of bone, the wear is due tomechanical friction as well chemical reaction. In either case, there isvalue in ascertaining the breakdown of the surface of bone or of anartificial or natural bone replacement. As described in FIG. 11, therewould be value in compound fragile tags but in this case such multiplefragile tags would be separated by location rather than substance in acapsule so as to allow assessment of where wear is occurring as well asdegree of wear in order to assess the impact of movement in which thepatient typically engages. Additionally, since the antenna of thefragile RFID tag is required for acquiring the RF power, design of theantenna so that wear degrades the functionality of the fragile tag'santenna (by shortening its length) prior to complete failure may be anappealing feature in some applications. Additional advantage comes fromusing the motion of the tag relative to a worn monitor to identify andrecord motion (to warn the patient of inappropriate or excessive motion)as taught in the related case of tire motion by U.S. Pat. No. 6,748,797(Breed et al.) and U.S. Pat. No. 6,538,566 (Morand et al.) until suchtime as the tag is worn away.

FIG. 12 b illustrates in greater detail the concept that the fragile tagcan be designed so it is enabled by a worsening condition before it isdestroyed. By interposing an RF blocking layers 241 between the fragileRFID tags 10 and the medicine 21 thus completely blocking the tags toexternal resonance, the fragile RFID tag would indicate a worseningcondition first by being inactive, then active, then (in a terminalcondition) by being again inactive as it is destroyed. Such blockinglayers can be composed of any radio frequency blocking (in the case ofthe fragile RFID tag) or other wavelength blocking or dampening materialas appropriate. Typical of such blocking materials would be a Faradaycage composed of a fine weave of gold wire, a foil of such blockingmaterial (and others that have the property of conductance and beingcapable of safe ingestion.) By using multiple fragile RFID tags andlayers, increasing amounts of specific wear and related information canbe extrapolated.

An additional feature is the possible use of the embedded tag to monitorinternal vibration in much the same manner as the Thermin listeningdevice referred to in the background. Such vibration monitoring devices,functioning as a miniature stethoscope, can be remotely queried asoriginally used by Thermin in his U.S. Moscow embassy listening device.

It should be noted that fragile tags may not only be embeddedsurgically, but may be embedded by shooting or jabbing the body toinsert the fragile RFID tag, thereby providing a safe and convenientmethod for testing the state of a body of a person or animal that wouldotherwise not cooperate in such test. An example of such an applicationwould be an uncooperative animal that needs to be tested by aveterinarian or tagging an animal in the wild.

Other embodiments of mechanical interaction could be a fragile tag whosefragility is derived from response to external pressure. A typicalapplication for such a fragile tag would be where following beingembedded, such a fragile tag would function until a loss of bloodpressure below a set limit occurred at which point the tag would bedestroyed, giving an immediate indication of the metabolic state of therecipient of the fragile tag. Similar applications can be extrapolatedfor loss of air pressure in the lungs.

Other embodiments of mechanical interaction could further include afragile tag that fails when temperature exceeds a certain limit.Compound fragile tags of this type could provide a rapid means ofremotely and automatically monitoring internal body temperature.

An embodiment that combines aspects of mechanical and chemical fragilityis the bio-reactive fragile tag. A casing, substrate, or component ofthe fragile tag would be designed to support the growth of a specificmold, fungus, bacteria or virus. The destruction of the fragile tagwould then indicate the presence of the organism.

Not illustrated, but mentioned, is the means of using multiple circuitsconnected to a single antenna such that wear will successively disableone identification circuit (by breaking a connector) while enablinganother (by breaking a barrier).

Surgically imbedded fragile RFID tags are not limited to attachment tobone or artificial implants to check for wear. They may also be attachedto medication that is designed for slow release over a long period oftime. For example, a pellet of medication implanted at a tumor site mayincorporate a fragile RFID tag to detect the rate of release of themedication from the pellet, or the exhaustion of the medication.

FIG. 13 illustrates an alternate embodiment of the concept of valuablefragility in medical tagging. In this case the tag 210 is not passivelyderiving its power from sympathetically resonating to an external RFsource, but instead is powered by either an internal power source 250 inthe capsule (as shown in the figure) such as a battery or a battery thatis also an antenna as taught by U.S. Pat. No. 6,700,491 (Shafer) ordevice for extracting power available from its environment through meansother than RF broadcast. The desirability of this more complex andexpensive variant rests in the value of being able to dispense with theantenna and the external application of power, allowing passivemonitoring systems. It should be noted that the value of fragility forsuch a device continues since the same functional value is provided bytracking its structured breakdown (as well as adding the feature that itdoes not need to be retrieved.)

The capsule may contain a power source, like the given “Pillcam,” or ameans of extracting power from the environment. Means of extractingpower from the environment can be external fields such as a magneticfields, acoustic stimulation, body heat, mechanical motion converted toenergy such as piezoelectrics, or chemical reactions with substances inthe body. However, unlike products such as the Pillcam, the capsulewould be composed of or contain fragile tag components, such as“designed for failure” elements of the circuit as mentioned withreference to FIG. 12 b, that would affect the output of the capsule. Asmentioned with reference to FIGS. 11 and 12 a, selective breakdown ofparts of the circuit could alter the identification signal emitted bythe capsule thus allowing creation of a “single use” ingested monitoringsystem.

It should again be noted that the signal emitted by the capsule does nothave to be in the RF range, but may acoustical, in the optical or otherpart of the wavelength spectrum.

FIG. 14 illustrates an additional (beyond antenna breakdown) form offragility useful for identifying the existence of specific compounds.The illustration depicts a device where multiple ID circuits 12 of theRFID tag are connected to a single antenna 16 for transmission by meansof connectors 260 composed of reactive compounds such as theaforementioned gold conductive traces that are left exposed to theenvironment that result in the signal defined by the circuit beingaltered by the reaction with the surroundings. Compounds such as metalsand metallic polymers can function by dissolving rapidly (in essence,cutting the trace to one circuit), and preferentially acting as a formof transistor by enabling the electrical flow or responding to theenvironment in a micromechanical manner (equivalent to opening orclosing a switch). Examples of this function would be where theprotective layer varies by thickness so that one (or more traces) is“cut” before another or where the protective material is chosen suchthat a specific compound in the in vivo environment causes it todissolve and expose the reactive material of the trace.

In keeping with the teaching with reference to FIG. 13, not illustratedbut easily anticipated, is the use of some power source 250 other thanan RF antenna 16 and the connectors 260 functioning by enabling thecircuit power from such power source 250 in addition to or instead ofthe connection to the RF antenna 16.

It should be noted that the external RF monitor that provides power tothe fragile RFID tag circuit, could be used to do work. An example isthe use of the monitor to initiate a breakdown of the fragile tag(through acoustic vibration or RF radiation and heat) with suchbreakdown resulting in the breakdown of a barrier that keeps thecontents of the capsule from mixing with the environment or breakdown ofthe antenna. Another mechanism for such a release would be the case ofmicromechanical release, where the failure of the fragile tag eliminatesthe source of power to micromechanical device that is acting as a gatewhich then causes the release of an agent such as a medicine throughdirect action (the failure of the fragile tag to keep closed a path toan internal reservoir of an agent) or through external mediation wherethe failure of the tag is monitored and triggers an external devicewhich automatically inject an active agent into the body or where theexternal device turns on a field or source of radiation that activates acomponent already within the body.

FIG. 15 illustrates a fragile tag designed to respond to externalacoustical stimulation 270 (not be confused with “acoustic tags” whichare audio signals combined with low frequency noise for the purpose ofidentification. See U.S. Pat. No. 6,301,364 (Lowmiller et al.)). Sincethe essential functionality of the fragile tag begins with echoing ageneric signal, circuit-less sympathetic resonance can be used toachieve the aims of this invention. This illustration suggests theconcept by schematically depicting a device such as a tuning forkstructure 280 embedded in the base 290 and placed in a capsule filledwith liquid. When the capsule disintegrates so does the tuning forkindicating completion of the medicine taking process. This embodimentbenefits from the fact that acoustically resonant materials areroutinely organic and found in nature and thus materials such as fibroussubstances suitable for ingestion are readily found.

Not shown but easily anticipated by the teaching in FIG. 15 is the useof acoustically resonant voids and spaces in the substance of medicine(regardless of the material being a tablet, capsule, lozenge or otherform so long as the medicine has a sufficiently rigid structure). Alsonot show but easily anticipated by FIG. 15 is the use of resonantthreads or strings under tension.

FIGS. 16A and 16B illustrate the use of an embedded fragile tag 300designed to operate with an external infrared (or acoustic or opticalwavelength) source. The infrared reflective tag is located sufficientlyclose to the surface of the skin that an infrared, terahertz, optical oracoustic laser source tuned to the proper frequency will reflect off thesurface tag in a manner that can be externally monitored. To enhance thestrength of the reflection, the fragile tag should be in the form ofretro-reflective or cube-corner material 310 such as that recentlytaught by U.S. Pat. No. 6,481,857 (Smith) and going back to U.S. Pat.No. 4,712,868 (Tung et al.) and others, yet earlier, to improve thestrength of the returning signal. The fragile IR tag would losereflectivity as it degrades. In addition, different parts of the tagcould be coated be different reactive coatings so that in addition tomechanical wear, chemical reaction could be monitored over time.

FIG. 17 illustrates the option of combining fragile tags with robustcomponents such as quantum dots 320. As previously mentioned indescription of FIG. 13, fragile tags may be combined with componentssuch as transmitters, circuits, mechanical components, micromechanicalcomponents and self-contained power sources that are not themselvesfragile. Hybrid forms of the device can be exercised in other fashionssuch as combining any of the fragile embodiments mentioned so far withrobust (as opposed to fragile) components and robust markers such asquantum dots, Cornell dots, or related compound release systems. QuantumDots and Cornell Dots used for biomarkers are discussed by C. Henry in“Quantum Dot Advances” found in the Chemical and Engineering News, Vol.81, No. 23 (Jun. 9, 2003) p. 10. Another form of hybrid system may beused where an embedded tag identifying the person is used, inconjunction with the monitors worn by the person, to add an additionallevel of assurance that the proper dosage is being reviewed by theintended recipient without tampering. See U.S. Pat. No. 5,923,572(Pollock) wherein an embedded tag process is suggested for use inrefueling automobiles (but without the aspect of a fragile RFID tag).

In this figure, the use of a reservoir of quantum dots 320 isillustrated. Quantum dots (as well as Cornell dots and similarfunctional nanomaterials) are designed respond to UV light in aparticular fluorescent range such that when the tag itselfdisintegrates, the quantum dot material composing the tag is released tospread through the body where it is eventually accessible to externalmonitoring. See U.S. Pat. Nos. 6,855,551; 6,326,144; and 6,306,610 (allto Bawendi et al.), which shows a combination of fluorescent light inthe proper frequency with a properly tuned monitor (sensor).

It should be noted that compound fragile tags connected with quantum dotreservoirs 320 of different colors may be advantage since the sequenceof breakdown or absence of breakdown of the medicine would provideuseful information concerning the rate of dissemination of the marker asthe quantum dots (in different colors) are released at different timesfor external Monitoring.

Finally, it should be noted that although embodiments of this inventionhave been discussed in terms of the in-vitro advantages of using asystem that takes advantage of the intentional fragility of the tag, itdoes not exclude ex-vitro embodiments since these may be found usefuland convenient. The same tag that can react to internal bodily chemicalstates is equally useful in checking bodily excretions, thus allowingthe creation of testing systems with a disposable reactive component fortesting feces, urine, blood, and all other manner of excretions with animproved level of safety and convenience. For example, the fragile RFIDtag may be dropped in the toilet after urination to check for thepresence of certain chemicals, without taking the urine sample to a labfor analysis.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the scope of theinvention

PARTS LIST

-   3 broadcast signal-   4 person/subject-   5 medical kiosk-   10 RFID tag-   12 circuit-   14 resonant cavity-   15 kiosk computer-   16 RFID antenna-   17 kiosk proximity detector-   18 substrate-   19 home computer-   20 container for medicine-   21 medicine-   22 tagged medicine with fragile RFID-   25 earpiece and boom-   30 monitoring device-   32 storage device-   34 emitter-   36, 36 a transceiver-   38 monitor support-   40 monitor “off” state-   42 computer-   44 monitor-   45 tagged medicine dispenser-   47 change state loop-   50 monitor activation-   52 collar-   53 lanyard-   54 belt-   55 change of state of monitor-   56 handheld device-   57 medicine dispenser-   58 overhead apparatus-   59 wall mount apparatus-   60 monitor time-out-   65 monitor off-   70 end-data signal-   75 detect tag-   80 read and combine data-   85 store data decision-   90 transmit data decision-   95 process data decision-   100 transmit data-   105 task completion-   110 monitor “off” check after task-   115 display results-   120 store data-   125 process data-   130 end state-   135 time check-   140 patient history-   145 correct medication time-   150 determine to take/not take medication-   155 take medication-   160 sensor location-   165 identify environmental conditions-   170 patient history comparison-   175 identify wrong medication or dosage-   180 identify environment for drug-   185 identify time for medication-   190 identify wrong combination of medications-   200 RFID tagged capsule-   210 three-dimensional coil-   220 compound capsule-   230 tag that breaks down due to mechanical wear-   240 bone surface tag-   241 RF blocking layer-   250 power source-   260 reactive compound connector-   270 external acoustical stimulation tag-   280 tuning fork-   290 base of tuning fork-   300 embedded tag-   310 cube-corner material-   320 quantum dots

1.-8. (canceled)
 9. A device to be imbedded in the body for monitoringwear or motion of a bone within the body, comprising at least one RFIDtag having an antenna subject at least to mechanical wear upon movementof the bone, whereby failure of the antenna indicates wear or movementof the bone.
 10. The device according to claim 9, further comprising RFsignal blocking material for blocking external signals from reaching thetag, the blocking material being subject at least to mechanical wearupon movement of the bone, whereby failure of the blocking materialenables the signals to activate the tag, thus indicating wear ormovement of the bone.
 11. The device according to claim 10, wherein theblocking material comprises first and second layers on opposite sides ofthe tag.
 12. The device according to claim 11 wherein the bone is partof a joint, further comprising a third layer of RF blocking material anda second RFID tag located between the first and third or the second andthird layers, whereby wear or movement of opposing members of the jointmay be monitored.
 13. The device according to claim 9, furthercomprising a medication associated with the tag.
 14. The deviceaccording to claim 9, further comprising a natural bone replacementsupporting the tag, and the bone replacement is part of a joint.
 15. Amedication for administration by mouth, comprising: a medicinal materialin an ingestible form; an antenna; a first ID circuit associated withthe material, the first circuit being connected to the antenna by afirst substance that responds to its environment; and a second IDcircuit associated with the material, the second circuit being connectedto the antenna by a second substance that responds differently to itsenvironment.
 16. The medication according to claim 15, wherein the firstand second circuits are RFID circuits connected to the antenna byconductive traces and the first and second substances overlie thetraces.
 17. The medication according to claim 16, wherein the traces arereactive with the environment.
 18. The medication according to claim 16,wherein the first and second substances are the same but have beentreated to respond differently to the environment of the medication. 19.The medication according to claim 16, wherein the first and secondsubstances are the same but of different thicknesses.
 20. The medicationaccording to claim 16, wherein the first and second substances dissolvedifferently in the environment of the medication.
 21. The medicationaccording to claim 16, wherein the first and second substances are thesame but have different textures.
 22. A medication for administration bymouth, comprising: a medicinal material in an ingestible form; and atleast one tag responsive to external acoustical stimulation associatedwith the material, the at least one tag comprising a device responsiveto external acoustical stimulation that ceases operation upon completionof ingestion of the medication.
 23. The medication according to claim22, wherein the device is in a capsule filled with liquid, whereby upondisintegration of the capsule the tuning fork disintegrates.
 24. Themedication according to claim 22, wherein the device is a tuning fork.25. A device to be imbedded in the body for monitoring wear or movementof a bone within the body, comprising at least one tag responsive to atleast one of an external infrared, optical or acoustical stimulation,the at least one tag comprising a retro-reflective or cube-cornermaterial that loses reflectivity in response to wear or movement of thebone.
 26. The device according to claim 25, wherein the tag is coatedwith at least one material that reacts chemically with the environment.27. The device according to claim 25, further comprising a medicationassociated with the tag.